CA1188935A - Method and apparatus for powder painting - Google Patents
Method and apparatus for powder paintingInfo
- Publication number
- CA1188935A CA1188935A CA000424185A CA424185A CA1188935A CA 1188935 A CA1188935 A CA 1188935A CA 000424185 A CA000424185 A CA 000424185A CA 424185 A CA424185 A CA 424185A CA 1188935 A CA1188935 A CA 1188935A
- Authority
- CA
- Canada
- Prior art keywords
- air
- powder
- mixture
- shaping
- path
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
- B05B5/025—Discharge apparatus, e.g. electrostatic spray guns
- B05B5/03—Discharge apparatus, e.g. electrostatic spray guns characterised by the use of gas, e.g. electrostatically assisted pneumatic spraying
- B05B5/032—Discharge apparatus, e.g. electrostatic spray guns characterised by the use of gas, e.g. electrostatically assisted pneumatic spraying for spraying particulate materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B1/00—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means
- B05B1/26—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means with means for mechanically breaking-up or deflecting the jet after discharge, e.g. with fixed deflectors; Breaking-up the discharged liquid or other fluent material by impinging jets
- B05B1/262—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means with means for mechanically breaking-up or deflecting the jet after discharge, e.g. with fixed deflectors; Breaking-up the discharged liquid or other fluent material by impinging jets with fixed deflectors
- B05B1/265—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means with means for mechanically breaking-up or deflecting the jet after discharge, e.g. with fixed deflectors; Breaking-up the discharged liquid or other fluent material by impinging jets with fixed deflectors the liquid or other fluent material being symmetrically deflected about the axis of the nozzle
Landscapes
- Electrostatic Spraying Apparatus (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
- Nozzles (AREA)
Abstract
ABSTRACT
A powder painting apparatus is disclosed. A body defines a central air-powder passageway. The air-powder mixture is deflected outwardly into a generally frusto-conical shape. A shaping air passageway in the body defines path which intersects the air-power mixture. The shaping air pressure is regulated to adjust the impact force of the shaping air striking the air-power mixture. The force adjusts the air-powder mixture to a predetermined pattern size.
A powder painting apparatus is disclosed. A body defines a central air-powder passageway. The air-powder mixture is deflected outwardly into a generally frusto-conical shape. A shaping air passageway in the body defines path which intersects the air-power mixture. The shaping air pressure is regulated to adjust the impact force of the shaping air striking the air-power mixture. The force adjusts the air-powder mixture to a predetermined pattern size.
Description
B~CKGRO~lND OF TIIE INVENTION
z 3 This invention relates to a method and apparatus for powder coating and 4 more specifically to a method and apparatus for eletroststic powder painting.
6 United States Patent No~ 4,228,961 discloses an electrvstatic powder painting head in which clean gas from an outer chamber is fed to the surf~ce of a strip 7 electrode. A monopolar corona dischEIrge current flows between the strip electrode 8 and the needle electrode. The current charges the nir-powder mixture rnoving 9 through the centrQl powder ejection port. The clean gas on the periphery is used 1~ to keep the strip electrode clean or powder free thereby insuring ~ proper corona 11 discharge current. The clean air is not used to regulate or shape the air-powder lZ mixture.
13 lJnited St~tes P~tent No. 4,235,381 discloses an electrostatic powder gun 14 having an auxili~ry compressed gas supply. The gas is passed to the nozzle and ionized so that upon being discharged at the tip of the elpparatus it assists in1~ placing the final charge on the powder.
17 It is preferable in powder painting to provide means for regulating the area 18 of the paint particle stream, which in turn regulates the ultimate pattern size on 19 the work piece or target. Various prior art appar~tus and methods have beenused in powder painting. Prior art powder appar~tus having means to shape the 21 pattern size of the ejected powder included both mechanic~l types and vortex air 22 ~ypes. One meeharIical type prior ~rt shaping means included ~n exterior adjwsting 23 sleeve which was normally cylindric~l and was reciprocated into and out of the 24 powder patternO The sleeve deflected the pvwder purticles into ~ ~orward direction.
26 Often erosion of the sleeve and fusion of the powder on the interior surîace of 28 the sleeve became a major problem~
27 AnGther type of prior art mechanical shaping deviee included the pl~cing of
z 3 This invention relates to a method and apparatus for powder coating and 4 more specifically to a method and apparatus for eletroststic powder painting.
6 United States Patent No~ 4,228,961 discloses an electrvstatic powder painting head in which clean gas from an outer chamber is fed to the surf~ce of a strip 7 electrode. A monopolar corona dischEIrge current flows between the strip electrode 8 and the needle electrode. The current charges the nir-powder mixture rnoving 9 through the centrQl powder ejection port. The clean gas on the periphery is used 1~ to keep the strip electrode clean or powder free thereby insuring ~ proper corona 11 discharge current. The clean air is not used to regulate or shape the air-powder lZ mixture.
13 lJnited St~tes P~tent No. 4,235,381 discloses an electrostatic powder gun 14 having an auxili~ry compressed gas supply. The gas is passed to the nozzle and ionized so that upon being discharged at the tip of the elpparatus it assists in1~ placing the final charge on the powder.
17 It is preferable in powder painting to provide means for regulating the area 18 of the paint particle stream, which in turn regulates the ultimate pattern size on 19 the work piece or target. Various prior art appar~tus and methods have beenused in powder painting. Prior art powder appar~tus having means to shape the 21 pattern size of the ejected powder included both mechanic~l types and vortex air 22 ~ypes. One meeharIical type prior ~rt shaping means included ~n exterior adjwsting 23 sleeve which was normally cylindric~l and was reciprocated into and out of the 24 powder patternO The sleeve deflected the pvwder purticles into ~ ~orward direction.
26 Often erosion of the sleeve and fusion of the powder on the interior surîace of 28 the sleeve became a major problem~
27 AnGther type of prior art mechanical shaping deviee included the pl~cing of
2~ a powder deflector in the center of the powde~air mixture and att~ching a rod 29 to the deflector. The rod normally exited the re~r of the pow~er gun. Pattern
3~;
adjustment was accomplished by moving the deflector closer to or further away 2 from the nozzle opening.
3 A prior art vortex air shaping means is shown in Fig. 5 of the present
adjustment was accomplished by moving the deflector closer to or further away 2 from the nozzle opening.
3 A prior art vortex air shaping means is shown in Fig. 5 of the present
4 drawings. A similar type vortex air structure is disclosed in United States P~tent No. 3f940,Q61. Referring to Fig. 5, the prior art spray gun A has a central ~ir-8 powder passageway B, a centrally disposed diffuser C and a nozzle D. The nozzle 7 D defines a plurality of vortex air p~ssages E which are in communication with a 8 clean air chamber F. As the air-powder mixture, in the Fig. S ~un, moves around 9 the diffuser C, it is enga~ed by compressed vortex air from the passages E. The vortex air strikes the air-powder mixture tangentially and causes the ai~powder 11 stream to assume a whirling movement. In this type of prior Qrt structure, as 12 the force of the tangential vo~tex air increases, the down stream area is increased.
13 When the vortex air force is reduced, the down stream area of the air-powder 14 mixture is reduced in eross sectional area.
Patent No. 3,964,683 discloses another prior art electrostatic spray apparatus 1~ for the deposition of powdered coating material. This patent is directed to a 17 pneumatic saftey interlock feature.
The present invention is a powder spray gun app~ratus whieh is normally ~
21 high voltage electrostatic type powder spray gun. The spr~y gun includes ~ remotely 22 controlled shaping feature, whereby the pattern size of the air-powder mixture 23 leaving the central region of the gun nozzle may be adjusted or regulated.
24 In a preferred form of the invention, a flared diffuser is positioned within the nozzle assembly of a powder gun. A powder gunf according to the inllention, æ~ may b~ either a manually operated gun or nn automatic gun. The flared diffuser 27 turns the air-powder mixture sharply outwardly.
28 A shaping air snnulus which is in communicQtion with a clean compressed air supply is defined by the noz~le assembly. The shaping annulus is in the shape 3~
, ) ,,~, ,.,: ., of a cylinder hRving its major axis p~rallel and normally coincidental with the 2 longitudinal axis of the central alr-powder passflgeway of the gun.
3 Compressed air which is discharged from the shaping air annulus impacts 4 the air-powder mixture with sufficient force to shape the downstream pattern 6 size. According to the present invention, increasing the nir pressure of the sir discharged fron~ the shaping nir annulus increases the impact force and rsduces 7 the cross sectional area and the resulting p~ttern area of the ~i~powder mixture.
8 Decreasing the air pressure and impact force increnses the resulting pattern 9 ~rea. It has been found that this novel method results in greater transfer efficiencies p~rticularly when large patterns are required.
11 Accordingly, it is an object of the present invention to provide a powder 12 painting method and apparatus resulting in greater transfer ef~iciencies.
13 Another object of the invention is to provide an electrostatic powder coating 14 apparatus having a remotely controlled air-powder shaping me~ns.
Another object of the present invention is to provide an electrostatic powder 1~ apparatus in which mechanical movable components are not used to vary the .7 powder p~ttern size.
18 Another object of the present invention is to proYide ~n improved eleeerostatic ~ g powder apparatus in which shaping air is utilized during the less frequent times when a reduced p~ttern size is an operational requirement.
~1 Other objects and advantages of the invention will become apparent f~rn2æ the following detailed àescription, with reference being made to the ~ccompanying 23 drawings.
24 BRIEF I)ESCRIPTION OF THE DR WINGS
Fig. 1 is an elevational view of an electrostatic powder apparatus for the 8~ deposition of a powder material on a wcrkpiece in accordance with a preferred 27 embodiment of the invention.
~8 Fig. 2 is ~n exploded YieW showing individual major components of the 29 apparatus of Fig. 1;
~0 I~
35;
Fig. 3 is a ~ragmentary cross-section~l view of the apparatus of Fig, 1, 2 shown on an enlarged scale;
3 Fig. 4 is a cross-sectional view taken along line 4-4 of Fig. 3; and4 Fig. 5 is a fragmentary, cross-sectional view, similar ~o Fig. 37 and showing a prior art electrostatic handgun having a vortex air shaping device.
DESCRIPTION OF THE PREFERRED EMBODIMENT
7 Referring to Figs. 1 and 2 a handgun 1;0 for the electrostfltic deposition of 8 a powdered coating material, such as paint, is shown. It is understood that the 9 handgun l0 is only one embodiment of the present inventionO The present invention may be used in automatic painting apparatus rather than in the manual handgun 1 1 shown.
12 The handgun l0 incluàes a gun body ll and a barrel 12 haYlng a front se~tion 13. Referring to Figs. 2 and 3, an electrode holder 15, mounting an electrode 1614 is received by the front section 13. A nozzle assembly l8 includes an inner nozzle member 19 and an outer nozzle member 20 whieh are press fit together.
1~ The noz~le assembly 18 defines a cylindrical recess 2~ which recelves a 17 diffuser 23. As best shown in Fig. 4, the diffuser 23 includes legs 24 which engag~
18 the cylindrical recess 22 in a seated position. During normal operation, the diffuser 1g 23 does not move longitudinally with respect to the longitudinal axis 27 of the ~0 barrel 12. The diffuser 23 includes a flared end 28. Referring to Fig. 39 the 21 handgun l0 includes a cylindrieal powder tube 29 which mates with a cylindrical ~2 recess 30 which is defined by the electrode holder 15. The recess 30 discharges 23 into a powdel passageway 31 which is defined by the nozzle assembly 18. During 24 operation, an air powder mixture is pumped through the aligned passageways defined by the tube 29, the cylindrical recess 30 and the passageway 31 As tlhe 2~3 air powder mixture moves along the longitudinal axis 279 the diffuser 23 ~nd its 27 flared end 28 deflect the air powder mixture sharply angularly outwardly into a 28 ~rusto-conical shape.
The gun 10 includcs a power supply circuit, gener~lly indic~ted as 33 and 2 having a current limiting resistor 34. The power supply circuit 33 includes biu~ing 3 springs 35 and 36 which are in electrical communication with the electrode 16.
4 The present handgun 10 includes safety valving me~ns generally indicated by the reference number 40. The safety valving means 40 senses air pressure at the face 41. The safety valving means 40 shuts off both the powder supply and 7 the electrical power as soon as the nozzle ~ssembly 18 is loos~ned or removed 8 frorn the gun 10.
9 Referring to Fig. 3, a compressed air chamber 42 is defined by the front section 13 of the handgun~ The clean air supplied to this charnber normally ranges ll between 0 psig and 40 psig. The nozzle assembly 18 defines an annular shaping 12 air cavity 43 which discharges~through a shaping air annulus 44. The air annulus 1~ 44 is preferably between .1)05 inches wide and .025 inches wide"Nith the preferable 14 width in the present embodiment being .015 inches. The shaping air annulus 44 extends in a direction parallel to the longitudinal axis 27. When shaping air is1~ discharged through the air annulus 44 it is discharged along a cylindrical path 17 which has its major axis coinciding with the longitudinal axis 27. Referring to 18 Fig. 39 the shaping air pnth P intersects the frust~conical air powder path S. A
19 plane r which is perpendicular to both the longitudinal axis a7 and the pnth P
intersects the ~rust~conical air-powder path S and defines an acute angle R, 2} which in the present embodiment Is 23o However, the angle R may vary7 norrnally 22 falling between 15 ar~d 30 , with a preferQble range between 20 Qnd 25.
~3 A plurality Gf circumferentially spaced holes 46 are defined by the inner 24 member 1g of the nozzle assembly 18 and are in communication with the shaping air cavity 43. The other end of the holes 46 are in communication with an ~nnular 2~ air chambel 47 which in turn communicates with the compressed ~ir chamber 42 ~7 through passageways, one of which is indicated by dashed lines at 4~ Therefore, 28 the air cavity 43 is in full communication with the compressed air chamber 42 29 through the holes 46, the annular chamber 47 and the passageways 48.
~ j ,. . .
,,", - _ When using an automatic system9 the air pressure within the compressed 2 air chamber 42 and consequently the shaping air cavity 43 is regulated at a remote 3 location. It is not necessary to manually adjust a rod or manually adjust the longitudinal positioning of a deflector mechanism to shape the ai~powder mixturebeing discharged from the gun.
In the present embodiment, the air pressure in the chamber 42 and cavity 7 43 is adjusted between 0 psig and 40 psig. As the air-powder mixture passes8 through the powder tube 29 and is deflected outwardly in the frust~conical shape 9 along the path S, the shaping air is discharged from the shaping air annulus 44 into the cylindrical path P. The shaping air intersects the frusto-conical path S
11 arld impacts the air-powder mixture. The impact force drives the air-powdermixture into patterns of a sm~ller area as the air pressure is increased. If the13 air pressure is decreased, the downstream pattern size incl eases with the maximum ~ 4 pattern size being present when the air pressure reaches û psig. It has been âound that the transfer efficiencies, particularily in the larger pattern sizes is greatly 1~ improved by the prescnt method and apparatus.
17 Transfer efîiciency is the amount Qf powder placed upon the workpiece 18 compared to the amourlt of powder passing through the spray apparatus. The 19 following test results, while not represented as covering all prior art app~ratus nor covering all parameters of operation, indicate that e~t the largest pattern 21 slze, where many industrial powder painting operations occur the apparatus,22 according to the present invention (shown in Fig. 3 and identified as "DeVilbiss 23 FLo~) has a signifieantly higher transfer efficiency.
2~S .
~0 MAXIMUM
TRANSFER EFFECTIV~ ~LOW
TESr GUN EFF5CIENCY PATTERN RATE
DeVilbiss FL. 91% 19 in. 2ao gr./min.
3 DeVilbiss Standard 81% 15.5 in. 200 gr./min.
4 N 84% 19 in. 200 gr./min.
G 78% 16 in. 200 gr./min.
The DeVilbiss Standard EHP-504 apparatus is the prior art apparatus, which 7 uses vortex air for shaping the pattern size. This apparatus is shown in ~ig. 4.
8 The "N~' unit uses replaceable diffusers having different diameters to ad~ust g pattern size.
lQ The "GI' unit uses a diffuser which is movable along the longitudinal axis of ll the nozæle to vary the pattern size.
12 During operation, the electrode 16, in the present embodiment, electro-statically charges the particles being discharged from the gun 10.
14 It will be appreciated that although a single preferred embodiment of the improved method and apparatus has been described, various modifications and l~ changes may be made without departing from the spirit and scope of the invention 17 hereinafter claimedO
~9 2~1 2g ~; _
13 When the vortex air force is reduced, the down stream area of the air-powder 14 mixture is reduced in eross sectional area.
Patent No. 3,964,683 discloses another prior art electrostatic spray apparatus 1~ for the deposition of powdered coating material. This patent is directed to a 17 pneumatic saftey interlock feature.
The present invention is a powder spray gun app~ratus whieh is normally ~
21 high voltage electrostatic type powder spray gun. The spr~y gun includes ~ remotely 22 controlled shaping feature, whereby the pattern size of the air-powder mixture 23 leaving the central region of the gun nozzle may be adjusted or regulated.
24 In a preferred form of the invention, a flared diffuser is positioned within the nozzle assembly of a powder gun. A powder gunf according to the inllention, æ~ may b~ either a manually operated gun or nn automatic gun. The flared diffuser 27 turns the air-powder mixture sharply outwardly.
28 A shaping air snnulus which is in communicQtion with a clean compressed air supply is defined by the noz~le assembly. The shaping annulus is in the shape 3~
, ) ,,~, ,.,: ., of a cylinder hRving its major axis p~rallel and normally coincidental with the 2 longitudinal axis of the central alr-powder passflgeway of the gun.
3 Compressed air which is discharged from the shaping air annulus impacts 4 the air-powder mixture with sufficient force to shape the downstream pattern 6 size. According to the present invention, increasing the nir pressure of the sir discharged fron~ the shaping nir annulus increases the impact force and rsduces 7 the cross sectional area and the resulting p~ttern area of the ~i~powder mixture.
8 Decreasing the air pressure and impact force increnses the resulting pattern 9 ~rea. It has been found that this novel method results in greater transfer efficiencies p~rticularly when large patterns are required.
11 Accordingly, it is an object of the present invention to provide a powder 12 painting method and apparatus resulting in greater transfer ef~iciencies.
13 Another object of the invention is to provide an electrostatic powder coating 14 apparatus having a remotely controlled air-powder shaping me~ns.
Another object of the present invention is to provide an electrostatic powder 1~ apparatus in which mechanical movable components are not used to vary the .7 powder p~ttern size.
18 Another object of the present invention is to proYide ~n improved eleeerostatic ~ g powder apparatus in which shaping air is utilized during the less frequent times when a reduced p~ttern size is an operational requirement.
~1 Other objects and advantages of the invention will become apparent f~rn2æ the following detailed àescription, with reference being made to the ~ccompanying 23 drawings.
24 BRIEF I)ESCRIPTION OF THE DR WINGS
Fig. 1 is an elevational view of an electrostatic powder apparatus for the 8~ deposition of a powder material on a wcrkpiece in accordance with a preferred 27 embodiment of the invention.
~8 Fig. 2 is ~n exploded YieW showing individual major components of the 29 apparatus of Fig. 1;
~0 I~
35;
Fig. 3 is a ~ragmentary cross-section~l view of the apparatus of Fig, 1, 2 shown on an enlarged scale;
3 Fig. 4 is a cross-sectional view taken along line 4-4 of Fig. 3; and4 Fig. 5 is a fragmentary, cross-sectional view, similar ~o Fig. 37 and showing a prior art electrostatic handgun having a vortex air shaping device.
DESCRIPTION OF THE PREFERRED EMBODIMENT
7 Referring to Figs. 1 and 2 a handgun 1;0 for the electrostfltic deposition of 8 a powdered coating material, such as paint, is shown. It is understood that the 9 handgun l0 is only one embodiment of the present inventionO The present invention may be used in automatic painting apparatus rather than in the manual handgun 1 1 shown.
12 The handgun l0 incluàes a gun body ll and a barrel 12 haYlng a front se~tion 13. Referring to Figs. 2 and 3, an electrode holder 15, mounting an electrode 1614 is received by the front section 13. A nozzle assembly l8 includes an inner nozzle member 19 and an outer nozzle member 20 whieh are press fit together.
1~ The noz~le assembly 18 defines a cylindrical recess 2~ which recelves a 17 diffuser 23. As best shown in Fig. 4, the diffuser 23 includes legs 24 which engag~
18 the cylindrical recess 22 in a seated position. During normal operation, the diffuser 1g 23 does not move longitudinally with respect to the longitudinal axis 27 of the ~0 barrel 12. The diffuser 23 includes a flared end 28. Referring to Fig. 39 the 21 handgun l0 includes a cylindrieal powder tube 29 which mates with a cylindrical ~2 recess 30 which is defined by the electrode holder 15. The recess 30 discharges 23 into a powdel passageway 31 which is defined by the nozzle assembly 18. During 24 operation, an air powder mixture is pumped through the aligned passageways defined by the tube 29, the cylindrical recess 30 and the passageway 31 As tlhe 2~3 air powder mixture moves along the longitudinal axis 279 the diffuser 23 ~nd its 27 flared end 28 deflect the air powder mixture sharply angularly outwardly into a 28 ~rusto-conical shape.
The gun 10 includcs a power supply circuit, gener~lly indic~ted as 33 and 2 having a current limiting resistor 34. The power supply circuit 33 includes biu~ing 3 springs 35 and 36 which are in electrical communication with the electrode 16.
4 The present handgun 10 includes safety valving me~ns generally indicated by the reference number 40. The safety valving means 40 senses air pressure at the face 41. The safety valving means 40 shuts off both the powder supply and 7 the electrical power as soon as the nozzle ~ssembly 18 is loos~ned or removed 8 frorn the gun 10.
9 Referring to Fig. 3, a compressed air chamber 42 is defined by the front section 13 of the handgun~ The clean air supplied to this charnber normally ranges ll between 0 psig and 40 psig. The nozzle assembly 18 defines an annular shaping 12 air cavity 43 which discharges~through a shaping air annulus 44. The air annulus 1~ 44 is preferably between .1)05 inches wide and .025 inches wide"Nith the preferable 14 width in the present embodiment being .015 inches. The shaping air annulus 44 extends in a direction parallel to the longitudinal axis 27. When shaping air is1~ discharged through the air annulus 44 it is discharged along a cylindrical path 17 which has its major axis coinciding with the longitudinal axis 27. Referring to 18 Fig. 39 the shaping air pnth P intersects the frust~conical air powder path S. A
19 plane r which is perpendicular to both the longitudinal axis a7 and the pnth P
intersects the ~rust~conical air-powder path S and defines an acute angle R, 2} which in the present embodiment Is 23o However, the angle R may vary7 norrnally 22 falling between 15 ar~d 30 , with a preferQble range between 20 Qnd 25.
~3 A plurality Gf circumferentially spaced holes 46 are defined by the inner 24 member 1g of the nozzle assembly 18 and are in communication with the shaping air cavity 43. The other end of the holes 46 are in communication with an ~nnular 2~ air chambel 47 which in turn communicates with the compressed ~ir chamber 42 ~7 through passageways, one of which is indicated by dashed lines at 4~ Therefore, 28 the air cavity 43 is in full communication with the compressed air chamber 42 29 through the holes 46, the annular chamber 47 and the passageways 48.
~ j ,. . .
,,", - _ When using an automatic system9 the air pressure within the compressed 2 air chamber 42 and consequently the shaping air cavity 43 is regulated at a remote 3 location. It is not necessary to manually adjust a rod or manually adjust the longitudinal positioning of a deflector mechanism to shape the ai~powder mixturebeing discharged from the gun.
In the present embodiment, the air pressure in the chamber 42 and cavity 7 43 is adjusted between 0 psig and 40 psig. As the air-powder mixture passes8 through the powder tube 29 and is deflected outwardly in the frust~conical shape 9 along the path S, the shaping air is discharged from the shaping air annulus 44 into the cylindrical path P. The shaping air intersects the frusto-conical path S
11 arld impacts the air-powder mixture. The impact force drives the air-powdermixture into patterns of a sm~ller area as the air pressure is increased. If the13 air pressure is decreased, the downstream pattern size incl eases with the maximum ~ 4 pattern size being present when the air pressure reaches û psig. It has been âound that the transfer efficiencies, particularily in the larger pattern sizes is greatly 1~ improved by the prescnt method and apparatus.
17 Transfer efîiciency is the amount Qf powder placed upon the workpiece 18 compared to the amourlt of powder passing through the spray apparatus. The 19 following test results, while not represented as covering all prior art app~ratus nor covering all parameters of operation, indicate that e~t the largest pattern 21 slze, where many industrial powder painting operations occur the apparatus,22 according to the present invention (shown in Fig. 3 and identified as "DeVilbiss 23 FLo~) has a signifieantly higher transfer efficiency.
2~S .
~0 MAXIMUM
TRANSFER EFFECTIV~ ~LOW
TESr GUN EFF5CIENCY PATTERN RATE
DeVilbiss FL. 91% 19 in. 2ao gr./min.
3 DeVilbiss Standard 81% 15.5 in. 200 gr./min.
4 N 84% 19 in. 200 gr./min.
G 78% 16 in. 200 gr./min.
The DeVilbiss Standard EHP-504 apparatus is the prior art apparatus, which 7 uses vortex air for shaping the pattern size. This apparatus is shown in ~ig. 4.
8 The "N~' unit uses replaceable diffusers having different diameters to ad~ust g pattern size.
lQ The "GI' unit uses a diffuser which is movable along the longitudinal axis of ll the nozæle to vary the pattern size.
12 During operation, the electrode 16, in the present embodiment, electro-statically charges the particles being discharged from the gun 10.
14 It will be appreciated that although a single preferred embodiment of the improved method and apparatus has been described, various modifications and l~ changes may be made without departing from the spirit and scope of the invention 17 hereinafter claimedO
~9 2~1 2g ~; _
Claims (7)
1. A method of powder painting using powder particles comprising the steps of: moving an air-powder mixture along a longitudinal axis deflecting the air-powder mixture angularly outwardly into a generally frusto-conical shape, and intersecting the frusto-conical air-powder mixture with a cylindrical path for a shaping air stream, such cylindrical path having a major axis coinciding with such longitudinal axis, said shaping air stream having sufficient force to impact the air powder mixture and shape the outer periphery of said mixture, whereby the downstream pattern size is regulated to a predetermined size.
2. A method according to claim 1, including adjusting the force of the shaping air stream as it intersects the air-powder mixture to vary the downstream pattern of the air-powder mixture.
3. A method according to claim 2, including the step of electrostatically charging the powder particles.
4. A method, according to claim 3, wherein a plane which is perpendicular to such longitudinal axis and to such cylindrical path intersects said frusto-conical shaped air-powder mixture thereby defining en acute angle.
5. A method according to claim 3, wherein the pressure of the shaping air stream is variable between 0 and 40 psig.
6. A method according to claim 4, wherein said acute angle is between 20° and 25°.
7. An electrostatic powder painting apparatus comprising, in combination, a body assembly defining a longitudinally extending air-powder passage having a longitudinal centerline, a diffuser assembly positioned along such centerline adjacent the discharge end of said air-powder passageway, said diffuser assembly defining an angular path in communication with said air-powder passageway, said body assembly defining a cylindrical clean air passageway, which discharges air in an air path parallel to such centerline, such air path intersecting such angular path, whereby said clean air may impact said air-powder mixture moving along said angular path to shape such mixture to a predetermined size, and means for electrostatically charging said powder.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US37409282A | 1982-05-03 | 1982-05-03 | |
| US374,092 | 1982-05-03 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1188935A true CA1188935A (en) | 1985-06-18 |
Family
ID=23475247
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000424185A Expired CA1188935A (en) | 1982-05-03 | 1983-03-22 | Method and apparatus for powder painting |
Country Status (10)
| Country | Link |
|---|---|
| JP (1) | JPS58202060A (en) |
| AU (1) | AU553607B2 (en) |
| BE (1) | BE896532A (en) |
| BR (1) | BR8302206A (en) |
| CA (1) | CA1188935A (en) |
| DE (1) | DE3310983A1 (en) |
| FR (1) | FR2525927B1 (en) |
| GB (1) | GB2119287B (en) |
| IT (1) | IT1163284B (en) |
| MX (1) | MX158574A (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2138324B (en) * | 1983-04-18 | 1986-06-04 | Binks Bullows Ltd | Electrostatic spraying |
| DE3608415A1 (en) * | 1986-03-13 | 1987-09-24 | Gema Ransburg Ag | ELECTROSTATIC SPRAYING DEVICE FOR COATING POWDER |
| DE19625099A1 (en) * | 1996-06-24 | 1998-01-02 | Heidelberger Druckmasch Ag | Process for powdering a printed surface of a printing material |
| JPH10314624A (en) * | 1997-05-14 | 1998-12-02 | Nippon Parkerizing Co Ltd | Electrostatic powder coating gun |
| DE10321614A1 (en) * | 2003-05-14 | 2004-12-30 | P + S Pulverbeschichtungs- Und Staubfilteranlagen Gmbh | Coating process as well as powder nozzle and coating booth |
| US9895726B1 (en) | 2016-07-27 | 2018-02-20 | Whirlpool Corporation | Method for cleaning a food waste recycling bin of a food waste recycling appliance |
| USD1027351S1 (en) | 2016-03-09 | 2024-05-14 | Whirlpool Corporation | Food recycler |
| US10000429B2 (en) | 2016-03-09 | 2018-06-19 | Whirlpool Corporation | Method and apparatus for operating a composter device |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2966310A (en) * | 1959-06-30 | 1960-12-27 | Interplanetary Res & Dev Corp | Electrostatic deposition spray means |
| GB979102A (en) * | 1962-05-25 | 1965-01-01 | Thornycroft John I & Co Ltd | Improvements in and relating to the supply of liquid fuel in a finely divided state |
| GB1038865A (en) * | 1962-06-04 | 1966-08-10 | Sames Mach Electrostat | Improvements in electrostatic spraying apparatus |
| US3408985A (en) * | 1966-11-07 | 1968-11-05 | Interplanetary Res & Dev Corp | Electrostatic spray coating apparatus |
| DE1652456A1 (en) * | 1967-03-08 | 1971-08-26 | Technoimpex Magyar Gepipari Ku | High performance electrostatic liquid spray gun |
| FR2064604A5 (en) * | 1969-09-26 | 1971-07-23 | Tunzini | |
| JPS5145143A (en) * | 1974-10-16 | 1976-04-17 | Ransburg Japan Ltd | Funshapataanno choseiga kanona funtaitosoyofunshanozuru |
| US4169560A (en) * | 1975-03-29 | 1979-10-02 | Elektrostatische Spritz-- und Beflockungsgesellschaft G.F. Vohringer GmbH | Electrostatic spray gun for powdered material |
| FR2448942A2 (en) * | 1979-02-15 | 1980-09-12 | Air Ind | Electrostatic spray gun jet system - has low pressure air jet rotated around central high pressure liq. jet |
| ES468633A1 (en) * | 1978-04-07 | 1978-12-01 | Rosal Vila Juan | Devices for covering objects with electrostatic dust |
-
1983
- 1983-03-22 CA CA000424185A patent/CA1188935A/en not_active Expired
- 1983-03-25 DE DE19833310983 patent/DE3310983A1/en not_active Withdrawn
- 1983-03-28 AU AU12897/83A patent/AU553607B2/en not_active Ceased
- 1983-03-31 GB GB08308919A patent/GB2119287B/en not_active Expired
- 1983-04-13 MX MX196925A patent/MX158574A/en unknown
- 1983-04-20 FR FR838306468A patent/FR2525927B1/en not_active Expired - Lifetime
- 1983-04-21 BE BE0/210607A patent/BE896532A/en not_active IP Right Cessation
- 1983-04-28 BR BR8302206A patent/BR8302206A/en not_active IP Right Cessation
- 1983-05-02 IT IT20885/83A patent/IT1163284B/en active
- 1983-05-04 JP JP58078834A patent/JPS58202060A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| BR8302206A (en) | 1984-01-03 |
| JPS58202060A (en) | 1983-11-25 |
| FR2525927B1 (en) | 1990-03-23 |
| AU1289783A (en) | 1983-11-10 |
| DE3310983A1 (en) | 1983-11-03 |
| MX158574A (en) | 1989-02-15 |
| AU553607B2 (en) | 1986-07-24 |
| IT8320885A1 (en) | 1984-11-02 |
| IT1163284B (en) | 1987-04-08 |
| IT8320885A0 (en) | 1983-05-02 |
| GB2119287B (en) | 1985-10-16 |
| GB8308919D0 (en) | 1983-05-11 |
| BE896532A (en) | 1983-08-16 |
| GB2119287A (en) | 1983-11-16 |
| FR2525927A1 (en) | 1983-11-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0059045B1 (en) | Electrostatic powder spray gun nozzle | |
| US3589607A (en) | Electrostatic spray gun having an adjustable spray material orifice | |
| US5685482A (en) | Induction spray charging apparatus | |
| CA1136403A (en) | Electrostatic spray gun | |
| EP0720869B1 (en) | Spray gun with adjustable fluid valve | |
| EP0114064B1 (en) | Nozzle assembly for electrostatic spray guns | |
| US4478370A (en) | Air atomizing nozzle assembly | |
| US6276616B1 (en) | Fluid needle loading assembly for an airless spray paint gun | |
| CA1096909A (en) | Spray gun nozzle attachment | |
| EP0650766B1 (en) | Suction feed nozzle assembly for HVLP spray gun | |
| US3408985A (en) | Electrostatic spray coating apparatus | |
| CA2004257C (en) | Spray gun having a fanning air turbine mechanism | |
| US4545536A (en) | Apparatus for electrostatic paint spraying | |
| CA1264015A (en) | Flat spray nozzle for a spray gun | |
| US3843052A (en) | Pneumatically assisted hydraulic spray coating apparatus | |
| GB1518517A (en) | Electrostatic spray gun for powder | |
| JPH0239312B2 (en) | ||
| CA1188935A (en) | Method and apparatus for powder painting | |
| EP0378741B1 (en) | Improved paint spray nozzle | |
| EP0050531B1 (en) | Nozzle assembly for an electrostatic spray coating apparatus | |
| US5169070A (en) | Air directing ring for fluid spray gun air cap | |
| US4235381A (en) | Devices for covering objects with electrostatic dust | |
| JPH0342941B2 (en) | ||
| EP1066116B1 (en) | Spray gun with common control of fluid and air valve | |
| WO1991003320A1 (en) | Spraygun |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEC | Expiry (correction) | ||
| MKEX | Expiry |